Steroids containing the CH.sub.3 CO-residue of progesterone as substituent in the 17-position play a particular role in the field of pharmacologically active steroid compounds and in the synthesis thereof. This acetyl radical in compounds of the progesterone type may be obtained by synthesis starting from 17-one steroids. However, increasing significance is being attributed to synthesis processes in which, starting out in particular from natural steroid compounds of vegetable or animal origin, the originally relatively long-chain substituent in the 17-position is subjected to partial degradation. Thus, European Patent Application as laid open Nos. 004,913 and 0015,305 describe a process for the production of 17C-steroid-.alpha.-propionic acid compounds, particularly 3-oxo-pregna-4-ene-20-carboxylic acid (.DELTA..sup.4 -BNC) and/or 3-oxo-pregna-1,4-diene-20-carboxylic acid (.DELTA..sup.1,4 -BNC) by microbial side chain degradation on 17C-side chain steroid substrates of natural origin.
BNC-compounds of this type and of related types are still of greater molecular weight by the presence of the carbon atom in the 22-position (present here as a carboxyl group) than steroid compounds of the progesterone type. The utilization of corresponding BNC-compounds for the further synthesis of pharmacologically interesting steroid compound requires degradation of the carboxyl group in C22 or transformation of this substituent present on the C20 into the C20-carbonyl group.
So far as 3-acetoxy-5-ene-BNC is concerned, it is known that the carboxyl group present as a substituent in C20 may be removed by conventional acid degradation using Curtius' method, see Ber. 88 (1955) 883. The product of this degradation is the 20-amino-steroid compound. Its transformation into the 20-keto compound of the progesterone type is relatively complicated.
Many important BNC-compounds containing an additional ene-bond in the 17(20)-position can now be obtained through the degradation of C17-side chain steroid substrates, particularly of natural origin, by microorganisms. Thus U.S. Pat. No. 3,994,933 describes the production of 3-oxo-pregna-4,17(20)-diene-20-carboxylic acid (.DELTA..sup.4,17 -BNC), its lower alkyl esters and pharmacologically compatible salts. The acid is obtained by microbial side chain degradation of 17C-steroid compounds.
European Patent Application Nos. 81.1001460.0 and 81.100145.2 and U.S. Pat. No. 4,333,880 describe the production of 20-carboxy-pregna-1,4,17(20)-triene-3-one (.DELTA..sup.1,4,17 -BNC) by microbial side chain degradation on 17C-side chain steroid substances. In addition, transformation of the 20-carboxylic acid group into the corresponding ester or the carboxylic acid chloride is described therein.
The copending, commonly-assigned U.S. patent application Ser. No. 262,970, filed May 12, 1981, now abandoned in favor of the present continuation-in-part application, and entitled "New .DELTA..sup.17(20) -BNC-Compounds and a Process For Their Production," priority Austrian Application A-2534/80, filed May 12, 1980, and copending, commonly-assigned U.S. patent application Ser. No. 262,965, filed May 12, 1981, now abandoned in favor of its continuation-in-part Ser. No. 407,790, filed Aug. 13, 1982, entitled "New Pregnane-20-Carboxylic Acid Derivatives and a Process For Their Production," priority Austrian Application A-2535/80, filed May 12, 1980, describe new .DELTA..sup.4,17(20) - and .DELTA..sup.1,4,17(20) -BNC-compounds corresponding to the following general formula: ##STR1## in which A represents .alpha.-hydroxyl, .beta.-hydroxyl or, together with the C-atom substituted by A, a carbonyl group and X represents hydroxyl, OK where K is a salt-forming group, OR (where R is a hydrocarbon radical preferably containing no more than 20 carbon atoms and, more particularly, a lower alkyl radical), halogen, particularly chlorine or bromine, or NH.sub.2.
These applications also describe the process for introducing the oxygen function into the 11-position.
BNC-compounds, such as those provided with an oxygen function in the 11-position (particularly the 11.beta.-hydroxylated derivatives) may be the starting point for subsequent dehydration to introduce another double bond into the steroid ring skeleton. Under suitable conditions, this double bond is preferably formed in the 9(11)-position, cf, for example, copending, commonly-assigned U.S. patent application Ser. No. 262,971, filed May 12, 1981, now abandoned in favor of the present continuation-in-part, entitled "New Steroid-20-Carboxylic Acid Compounds and a Process For Their Production," priority Austrian Application A-2629/80, filed May 16, 1980.